Separable attachment-plug.



E G. K. ANDERSON.

SEPARABLE ATTACHMENT PLUG. APPLICATION FILED AUG. 10, 1909.

1 1 @g gQQ Patented July M, 1914 UNITED STATES PATENT OFFICE.

ERNST G. K. ANDERSON, OF CHICAGO, ILLINOIS, ASSIGNOR TO BENJAMIN ELECTRIG- v MANUFACTURING COMPANY, OF CHICAGO, ILLINOIS.

SEPARABLE ATTACHMENT-PLUG.

Specification of Letters Patent.

Patented July 14, 1914.

Application filed August 10', 1909. Serial No. 512,178.

To all whom it may concern.-

SON, a subject of the ing at Chicago, in the county of .Cook and State of Illinois, have invented new and useful Improvements in Separable Attachment-Plugs, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawing, forming a part of this specification.

This invention relates to improvements in separable attachment plugs, the object of the invention being to provide an, attachment plug of this type in whichthe means which normally hold the separable parts together are adapted to resist a direct longitudinalstrain tending to separate the parts i formed of insulating material, surrounding until considerable force is applied to pull them apart, said holding means nevertheless permitting the parts to separate slight strain is applied in such a way as to tend to bend or pry one part over the other.

Separable attachment plugs are frequently employed with such current consuming appliances as electric-heaters, fiat-irons and the like. When so employed an attachment plug is likely to be subjected to sudden strains which are so applied that the plug, if of ordinary construction, will not be separated. The ordinary forms of plug are adapted to separate only by reason of a direct longitudinal strain or a sudden jerk being exerted upon the conductors in a direction parallel, or substantially parallel, with the axis of the plug. In the use of flat-irons and the like, however, if the same be accidentally allowed to fall from a table or workbench the sudden strain communicated to the plug through the medium of the conductorsis not usually applied in a direction parallel with the axis of the plug or the socket into which the plug isinserted, but rather in a irection at nearly right angles therewith, especially if the socket extends straight out from the wall, as is frequently the case Where these devices are used. The result has been that the plug has failed to separate and the'socket has been damaged or pulled loose from its support, the crossing of the wires leading to the socket sometimes starting fires. With the device forming the subject of the present invention the parts separate readily when force is applied in such a way as to tend to bend the parts one over the'other.

whena.

In the accompanying draWingS Figure 1 I is a side elevational view of the device with the parts separated; Fig. 2 is a longitudinal sectional view of the device on an enlarged scale, showing the parts connected to each fother; and Fig. 3 is a cross sectional view of the same taken on the line 33 of Fig. 2, looking upward.

This plu comprises a ca member which is arranged to be inserted into an ordinary lamp-receiving socket, and another member, =which will be hereinafter termed the plug jmember, which is arranged to be inserted into the cap member, this lug member hav- ;ing suitable binding terminals to which the leading-out conductors are secured.

The cap member comprises a base 5 which is a metallic threaded ring 6. The

ithreaded ring has its'upper end bent over inward at opposite points designated 7, the *ears formed thereby extending into recesses .8 formed in the side of the base. {threaded portion of the ring 6 the latter exitends down for a short distance and is turned in under the lower end of the base at '9. The ring extends downward a farther short distance below the shoulder formed by Belbw the extending the ring inward at 9, thus forming a neck 10.v Surrounding the neck 10 is an insulating ring 11, the metal of the neck 10 being flanged outward below the ring 11 to hold-the latter in place. The ring 11 is knurled or roughened on its outer edge in order that the same may be firmly grasped when it is desired to screw the device into a socket. An insulating collar 11 extends up for a short distance from the ring 11., The

base 5 is prevented from coming out .of the threaded ring by the inturned ears 7 on the ring and the inwardly extending shoulder 9 on the same. 4

A central aperture 12, provided in the base, contains a barrel 13 in which is arranged. a compression springl, the latter being seated at its upper end against a plate 15', which engages a shoulder formed. by drawing in the metal of-the barrel at 16. The lower end of the spring 14 thrusts against a plunger 17 and tends to move the same downward. The plunger is limited in its downward movementby the engagement of a flange 18 on the plunger with an inwardly extending flange 19,on the lower end of the spring barrel. The plunger 17 ex- Y metallic ring 22 extends around the enlarged portion of the base and has its upper end drawn in at 23 over the shoulder formed by enlarging the lower'part of the base. This ring 22 extends up along the periphery of the smaller part of the base and is there divided by vertical slits into a number of re.- silient tongues 24. Each of these tongues is formed with an. outwardly exten ing hump. Below the base 21 the ring extends inward at 25 and from this point is carried downward at a smaller diameter thanits main portion, thus forming a neck 22. The neck 22 is threaded for the receptionof the threaded neck 26 of an insulating cap 27 This cap is made of rubber, vulcanized fiber or the like and, when the separable parts of the device are put together, engages around its upper edge the'under side of the ring 11 l/Vhen the plug portion of the device is thrust up into the chamber in the lower end of the cap ortion the resilient tongues 24 yield inwar ly to permit the same to pass through the neck 10 of'the threaded sleeve 6. After the parts have been thus put to gether the plug portion of the device is pre vented from falling out of the cap portion byv the engagement of the humps on the tongues 24 with the interior of the neck 10. The tendency of the spring-pressed plunger to thrust the lower portion of the device out holds the tongues in good electrical connect-ion with the neck 10 of the ring 6.

The base 21 of the plug portion of the device is formed with a cavity or depression in its side, the ring 22havin a portion 28 slitted vertically on each si e thereof and bent back into this depression. \Vithin the depression, on the inner side of the tongue 28, is located a nut 29 into which passes a binding screw 30 which extends through the tongue 28. The conductor 31 is brought up through the neck 26 of the insulating cap and extends into the depression in the base, being there secured under the head of the binding screw 30. Electrical connection is thus made between the resilient tongues 24 and the conductor 31 and, when the separable parts of the device are put together, between the threaded ring 6 and this conductor.

A passage 32 extends longitudinally through the base 21 for the accommodation of the secondconductor 33. This passage is contracted at its upper end and in the conserved th'at in the ger to tracted portion is arranged a hollow rivet 34 which holds in, place. ap-late 35 which hasa threaded opening for the reception of a binding screw 36. This screw extends down into a hole which leads centrally downward into the base. The second conductor 33 extends up through the hollow rivet 34 and has its bared end laid under a tact 16 of the device and the conductor 33.

Heretofore the interlocking parts which were carried by the two members of separable attachment plugs have been either arranged centrally with respect-to the two members, or have been disposed at two diametrically opposite points. It will be obpresent device the parts which hold. the separable members together are arranged 'circumferentially around the insertible member. Thus a strain which would tend to pry one member over the other would draw the interlocking parts away from each other along one side of the plug member, but would not be required to separate these members at all points around the device at the same time. This results in a marked difference between the action of my separable plug and that of any other separable plug of which I am aware. Furthermore, the tendency of the spring plunush the members away from each other adds to the readiness of the device to break apart when the impositively locking members are disengaged at any point around the periphery of the insertible member.

Having thus described myinvention, what I claim as new and desire to secure by Letters Patent, is: I

1; The combination of a cap having an end contact and a side contact, a plunger electrically connected with said end contact, a member adapted to be inserted into said cap, an end contact on said insertible me1nher for engagement with said plunger, a ring carried by said insertible member and having a portion thereof made yielding, and

means carried by said cap and electrically connected with the side contact of said cap and disposed for yielding locking engagement with the resilient portion of said ring.

2. The combination of a cap, an end con-' tact, a plunger electrically connected with said end contact, a side contact carried by said cap, a member insertible into said cap, binding terminals carried by said insertible member, an end contact on said insertible 'inember electrically connected with one of said binding terminals and disposed for engagement with said plunger, a resilient side contact on said insertible member electrically connected with another binding terminal,

and means carried by said cap and arranged for yielding locking engagement with the side contact of the insertiblemember, said means being electrically connected with the a' resilient side contact on said insertible member, and means carried by said cap and adapted for yielding holding engagement with said resilient side contact.

4. The combination with a cap having an end contact and a side contact, of, an insertible member having an end contact and a side contact, longitudinally yielding means for making electrical connection between the end contact of the cap and the end contact of the insertible member when the latter is inserted into said cap, and means for locking said member in said cap, said locking means being releasable upon a predetermined force being applied to said member in a direct pull, said locking means also making electrical connection between the side contact of.

the plug and the side contact ofthe cap.

5. The combination of a cap'having an end contact, an insertible member having an end contact, longitudinally yielding means for electrically connecting said end contacts with each other, a sidecontact on said cap, and a side contact on said member, said side contacts being arranged to electrically engage each other and lock the cap and insertible member together so as to be capable of separation upona predetermined force being applied to said lnsertible member in a direct pull. I

6. The combination of a cap having an end contact and a sidecontact, a member having an end contact }arranged to be brought into electrical connection with one of the contacts of the cap when the member and cap are put together, said member having also a side contact comprising a ring ex tending therearound and liavin resilient tongues thereon, and means carried by the cap with which said tongues yieldingly lock, said means being electrically connected with the other contact of the cap.

7. The combination'of a cap having an end cont-act and a side cont-act and having a recess formed with a restricted opening, a binding terminal carrying member having a portion formed for insertion into the chamber of the cap, means carried by said member and said cap respectively for electrically connecting one of the binding terminals with one of said cont-acts, means extending around said member for frictionally engagin the mouth of the chamber of the cap and tiereby holding the member in position in said cap, said means being electrically connected with'the other binding terminal, and means carried by the cap and disposed for electrical engagement with said last-named means and electrically connected with the other contact of the cap.

8. In an attachment plug the combination of a base provided with a shell, an insulating body member mounted'in the shell, said insulating body member being of less height than the height of the shell thereby leaving a portion of the interior surface of the shell exposed, a center contact mounted in the insulating body member, and a detachable cap provided with a center contact to contact with the center contact of the base and also provided with one or more contact-s to directlycontact with the exposed surface of the shell.

9. In an attachment plug'the combination of a base provided with a shell, a non-conducting guard ring secured to the upper edge of the shell, an insulating body member mounted in theshell, said insulating body member being of less height than the height of the shell thereby leavin a portion of the interior surface of the she I exposed, a center contact mounted in the insulating body member, and a detachable cap provided with a center contact to contact with thecenter contact of the base and also provided with one or more contacts to directly contact with the exposed surface of the shell.

10. In'an attachment plu the combination a i of a base provided with a s ell, an insulating body member mounted in the shell, said 1nsulating body member being of less height than the height of the shell thereby leaving a free portion of the surface of the shell to form one element of an electrical connection, a center contact carried by the insulating body member, having an electrical contacting surface of less length than that of the free portion of the shell, a detachable cap provided with a center contact to cooperate with the center contact of the base and with one or more contacts to contact with the free portion of the shell, thereby insuring that the center contact is disconnected before the shell contact.

In witness whereof, I have hereunto subscribed my name in the presence of two wit- 

